Motown and melodrama may seem like an odd entertainment pairing, but the folks at Mosley Street Melodrama have managed to come up with a funny and tuneful melange with their newest show.

The first half is the cornball original romp “Butch Cassidy and the Can’t Dance Kid, or, You Polka, You Brought Him” by prolific local playwright Tom Frye with all the usual bells and whistles of slapstick, broad humor and bantering with the audience.

But after the break, the evening heats up and then mellows out with “Motown Mania,” a revue of 1960s-1980s hits put together by Patty Reeder and directed with flair by Broadway veteran Karla Burns.

The same six people perform both halves of the show, and it’s sometimes surprising to realize that the jokers in crazy costumes doing shameless and ridiculous pratfalls in the first half actually have the pipes to pull off the sophisticated close harmonies and lead showcases of the second half. It makes us appreciate the diversity and depth of their talents even more.

The melodrama, directed by Cindy Summers, deals with the usual villain and hero antics, but Frye turns the form on its head this time by crafting the roles for women, both tussling over a hapless, helpless man.

Despite Paul Newman’s classic movie character, this Butch Cassidy – actually here called “Butch with an ‘I’ Cassidy” – is truly a bad guy, er, gal. As played by Jenny Mitchell, Butch is a masked outlaw in black gaucho pants and black hat who disguises herself as the persnickety, vinegary, long-skirted school board president, Olive Pitts, when she’s not skulking around plotting evil deeds.

Mitchell fearlessly throws herself into numerous quick changes between the two sides of her character, hilariously not always getting pulled together in time to dash back on stage. More than once, she needed to hold her skirt in place to prevent a wardrobe malfunction.

Going toe-to-toe with her is perky, blonde, Pretty-in-Pink Cecile Mae Hoggatt (Briley Meek), the sheriff’s daughter who runs the local telegraph office (although, ironically, relying on a cellphone herself). She aims to bring “Butch with an ‘I’ ” to justice.

Caught in a tug-of-war between them is cute, bespectacled wimp Walter (Steve Hitchcock), the new school marm, er, man teacher, whose students are the notoriously bratty Pickard Twins, Amy (Leah Swank-Miller) and J.D. (John Bates), which some folks claim stands for “juvenile delinquent.” Dressed in matching Orphan Annie/Andy blue shorts and red-and-white-striped tees, they prove they haven’t progressed beyond the Terrible Twos.

Rounding out the cast is Scott Noah in dual roles as blissfully oblivious Sheriff Hoggatt and, in drag, as the twins’ lecherous mom, who literally chases the new teacher around his desk to flirt with him.

The melodrama just about reaches the end when one of the characters forgets a line, and they decide to start over and run through it again, only this time, hilariously in fast-forward. It’s a well-oiled gimmick that is always good for pratfall giggles.

“Motown Mania,” on the other hand, represents a complete change of tone and pace as the six performers – men in crisp black suits with pastel shirts and women in dreamy mint-green chiffon – take us on a nostalgic journey through a dozen or so classics made famous by the likes of The Supremes, Rick James, Donna Summer and Gladys Knight and the Pips.

The singers trade off, each taking a solo or lead spot, and then singing backup for the others. Among particular highlights were Mitchell belting out “Midnight Train to Georgia” and Hitchcock using his high, clear falsetto for “Baby Baby.” Also terrific were the men’s medley built around “My Girl” and the women’s medley built around “Love Child.” One problem for me was the one-liner jokes between songs, particularly those about Michael Jackson. They were a distraction from the artistry.

Musical director Burns made sure that her singers paid attention to the background nuances as much as the foreground vocals to create the whole, balanced package – all well accompanied with flying fingers on the keyboards by Steve Rue.